Earth-moving machine



Oct. 1, 1946.

A. B. M FARLANE EARTH MOVING MACHINE 3 Sheets-Sheet 1 Filed Dec. 1, 1943 Oct. 1 1946.

A. B. MCFARLANE EARTH MOVING MACHINE Filed Dec. 1, 1943 KSh'eets-Sheet 5 6 a v 0 M E m a 4 w w m u m wvvw QoNo no mo D n n x H 6 3m, 9

Patented Oct. 1, 1946 UNITED STATES PATENT OFFICE? Arthur Burnard McFarlane, Harrow, England, assignor of one-half to Robert Lowe, Bexley Heath, England Application December 1, 1943, Serial No. 512,501 In Great'Britain November 23, 1942 3 Claims. 7 1

This invention relates to bucket wheel scrapers including a wheeled bowl or bucket adapted to be hauled by a tractor, a blade or scraper at the lower front edge of the bucket passing earth thereinto under a movable apron during scraping, and a tail-gate ejector spilling the earth from the bucket over the blade when required. Bucket wheel scrapers at present in'use comprise the rigid or-rear lift type in which the vertical position of the blade or depth of cut is adjusted by altering the relative position of the bucket and rear wheels, and the articulate or front lift type in which the wheeled frame carrying the bucket is articulated to effect such adjustment. Control by the operator on the towing tractor is exercised through the medium either of cables and/or a hydraulic system actuating fluid pressure cylinders on the scraper to move the front apron, adjust the vertical position of the blade and bucket and actuate'the tailgate.

The present invention is generally applicable to all such machines, although primarily intended for cable operated rigid or rear lift type scrapers, and has for its principal object to provide an improved construction inwhich the top of the bucket is open and free from obstruction by the operating mechanism so that when desired it may be loaded from say a drag-line excavator or other elevator, thus suiting the machine for carrying and spreading or dumping earth which .has been loaded in this way in addition to its normal dig and carry function as a scraper.

Further and favourable objects will appear from the following description.

In accordance with the present invention a bucket wheel scraper including a wheeled bucket, a blade or scraper atthe lower front edge of the bucket for passing dirt or earth thereinto under a movable front apron, and a tail-gate ejector for spilling earth from the bucket over the blade when required, is characterised by the provision of'means for automatically returning the tailgate to its position at the rear of the bucket after ejection so connected to the tail-gate as to tend to compensate or neutralise the moment produced by the resistance encountered, particularly by the lower part of the tail-gate, during ejection of the contents of the bucket, and so disposed as to leave the top of the bucket completely open and free from obstruction. i

Where a pair of coil compression springs is employed to actuate the return mechanism, they are conveniently housed in tubular casings extending laterally across the rear of the bucket and leading the cable from the longitudinal planes in which the carriages move along the upper edges of the bucket side walls on the one hand to the transversely disposed axes of the springs on the other. The spring housings or casings may be bracketed to the rear wall of the bucket either alongside each other or one above the other or--especially where it is desired to take maximum advantage of the space available to provide springs of greater length and stroke than could otherwise be accommodated within the overall width of the scraperthe axes of the spring housings may be oppositely inclined and staggered one behind the other, a cable passing from the upper end of each spring housing to its guide pulley aforementioned and thence to an arm upstanding from its tail-gate carriage so as to apply the desired compensating moment to'the carriage.

By utilising a pair of springs one connected to each tailgate carriage in the manner specified for effecting the tailgate return, individual adjustment of their initial or pre-compression may be readily arranged and in' addition to the compensation' effected for the resistance encountered by the tailgate when pushing out the contents of the bucket, by differentially adjusting the pre-compression of the respective springs so that there is a, greater resistance opposing the initial movement of the carriage on-that side of the bucket along which the tailgate operating cable passes from the front of the scraper, the tendency of thi carriage to move ahead of its companion may be countered and a smoothly running tailgate ensured.

When applied to a rear lift type scraper, a rigid yoke extends forwardly from the side walls of the bucket and is carried by the steerable wheeled forecarriage and mounts a transverse A frame for the sheaves over which passes the cable actuating the front movable apron, and it may be also the tail-gate, such A frame being if desired of conventional form except that it is disposed well forward so as not to obstruct the open top of the bucket between the top edge of the apron and the tail-gate.

The-invention will be further described with reference to the accompanying sheetsof explanatory drawings which illustrate an embodiment by way of example, and in which Figs. 1 to 3 show the preferred arrangement where the tail-gate return mechanism is actuated by springs extending laterally across the rear of the bucket,

Fig. 1 being a side elevation of the preferred scraper,

Fig. 2 is a rear view, and

Fig. 3 a plan thereof.

Referring now to the drawings, I generally designates the bucket having side wallsfl and Sbridged at the rear by a structure 4, a rigid yoke 5 extending forwardly from the side walls 2 and 3 of the bucket I and being carried by a steerable wheeled forecarriage 8 at the foot of the pillar 6. I indicates the road wheels of the steerable forecarriage 8 and I3 its tow-bar, which parts may be standard or conventional for attachment to the towing tractor (not shown), although preferably such forecarriage 8 mounting the wheels I comprises a rigid assembly-universally carried at the foot of the pillar E.

The rigid yoke 5 mounts in front of the bucket a transverse A frame 9 for the sheaves IQ over which passes the cable I! actuating the front movable apron I2, and this A frame may be of conventional form except that it is disposed well forward of the yoke 5 so as not to obstruct the open top of the bucket I between the top edge of the apron I2 and the tail-gate hereafter described.

I5 represents the rear wheels, of which there are four, arranged in two laterally spaced pairs at the rear of the bucket as more clearly shown in Fig. 2, although two only single wheels may be utilised, and I5 is the rear carraige, a fabricated box structure webbed for its reinforcement, which has arms II and I8 extending forwardly outside the bucket I and supporting same by means of aligned trunnions I8, the rear lift of the rear carriage It for adjusting the vertical setting or height of the bucket 2 being effected by a cable 29 passing over sheaves Or guides 2!, 22 and 23 along one arm of the yoke 5 to a multiple sheave box 24 arranged externally 0n the rear structure l of the bucket, and with which sheave box 24 cooperates a complementary sheave box 25 on the rear carriage to give the required mechanical advantage enabling fine and accurate adjustment of the vertical position of the bucket to be effected by the operator on the tractor via the cable 20.

Large section pneumatic tires are utilised for the road wheels and preferably as shown in Figs. 3 and 4 the front wheels I track with the outer wheel of the pairs of rear wheels I5. In cases where single rear wheels are utilised, the front wheels I would be arranged to track with such single wheels.

The bucket I is a folded and fabricated sheet metal structure and its floor may be arranged with a wood filling and reinforced with a number of webs rendering it strong enough to be loaded by an excavator when the machine is in use as a dumper or spreader, and the cutting blade which may be stepped or curved, is carried at the front edge of the floor beyond which the side walls 2 and 3, which can be used to carry scarifying teeth and side cutting blades and which preferably extend forwardly on each side of the front apron I2, being braced by a cross tube 3|.

The front apron I2 normally obtrudes the open front of the bucket and as will be more clearly seen from Fig. 3 is mounted for pivotal movement between the side walls 2 and 3 on hinge pins 32 near the upper edges thereof, the

relative disposition of the sheaves It] on the A frame 9 and hinges 32 about which the apron I2 rocks, enabling the cable II to lift the apron to a fully raised position in which the front of the bucket is completely open when the contents of the bucket are to be ejected by the tail-gate as when the earth is to be spilled over the blade 30 while the machine is being used as a spreader, or the apron may be set to any intermediate position when the bucket is being loaded over the blade at while the machine is being used as a digger or scraper.

40 represents the tail-gate proper which is formed of sheet metal and adapted closely to fit between the side walls 2 and 3 of the bucket and having its lower edge curved forwardly and adapted to scrape the bottom thereof during ejection, while normally, that is when the machine is in use as a scraper, such tail-gate is positioned within the bucket at the rear thereof against the rear structure 4. V

The sheet metal portion Iii of the tail-gate depends from a transom 4| mounted on wheeled carriages 52 and 43 riding guideways provided for the purpose on the upper edges of the respective side walls 2 and 3 of the bucket.

Such guideways are shown more clearly in Fig. 1 and comprise upper tread sections 44 upon which ride rollers 45 and 46 of the tail-gate carriages. Lower treads are also provided with the underside of which rollers 41 on the tail-gate carriages 32 and 43 engage, so that any tendency of the carriages to be derailed under the resistance encountered by the tail-gate 40 during its forward movement, is eliminated.

Such forward movement of the tail-gate to eject the contents of the bucket is effected by continued movement of the cable II, preliminary movement of which actuates the front apron I2 and which, after traversing a sheave 50 on such apron, returns to the sheave It at the head of the A frame 9 and passes thence under a guide pulley III in the middle of the A frame, over guide pulleys 5| and 52 carried by the yoke 5 and around pulleys 53 and 54 on the transom of the tail-gate 40 and thence forwardly along the offside of the bucket to a sheave pulley 55 aligned with the guide pulley 52 but on the opposite side wall of the bucket, and then back to an anchorage 48 on the transom II which also carries a spool 49 for spare cable. Forward movement of the cable II thus first raises the apron I2 and after lifting it to the full extent to open the front of the bucket, imparts forward movement to the transom AI and tail-gate 40 to eject the contents thereof.

The sheave boxes mounting the pulleys 5!, 52, 53, 54, 55, also each carry second pulleys over which the cable II passes to give the requisite mechanical advantage for accurate control of the tail-gate.

The transverse disposition of the transom 4| and tail-gate 40 is maintained and smooth fore and aft travel of the carriages 42 and 43 assured by rollers 38, 39 borne on vertical aXes near the front and rear of each carriage and riding the external vertical faces of treads on the side walls 2 and 3, while the forward limit of movement is determined by stops 3'I projecting upwardly from the side walls 2 and 3 and with which stops the front ends of the carriages abut.

It will be noted that, with the exception of the apron hinge pins 32, there are no working parts inside the scraper bowl or bucket, and that owing to the forward curvature of the tailgate 40, the bottom of the bucket is completely cleared during the forward movement of the tail-gate bythe time the stops 3'! are reached.

The return or rearward movement of the tailgate after ejection is effected in the embodiments illustrated by coil compression springs and in the preferred arrangement illustrated in Figs. 1 to 3, these springs are housed in tubular casings 56 and 51 disposed laterally across the rear of the machine above the rear wheel carriage It so that the top of the bucket is left free and unobstructed.

Two springs are preferably employed, each connected to its respective tail-gate carriage 42 and 43 in order that the resistance to forward movement of each carriage shall be uniform and remove twisting moment from the tail-gate, each spring 58 being a facsimile of the other housed within its casing 56 or 51 and actuated by a cable 60 at the olfside and BI at the near side of the machine, the cable 66 passing over a guide pulley 62 at the rear offside of the machine from the transverse axis of its spring 58 to the longitudinal axis of movement of its carriage 42, and the cable 6| changing direction over a similarly disposed pulley 63 at the near side.

As the tail-gate is moved forwardly to eject the contents of the bucket l, (by the cable II, the cables 60 and 6| compress the springs 58 and store energy therein for the return movement of the tailgate when the cable I l is released, and further, by reference to Fig. 1 it will be seen that the cables 60 and Mara connected to arms 64 upstanding from their respective carriages with the result that a counter-clockwise movement is exerted on the carriages which compensates or neutralises the clockwise moment produced by the resistance encountered by the tailgate 45 during its forward movement in ejecting the contents of the bucket.

As is shown more clearly in Fig. 3 the cable 6| passes from the arm 64 over the guide pulley 63 mounted at the open end of the casing 51 and then transversely inside the spring 58 to a follower 65 between which and an abutment 66 within the casing 56 the spring is compressed as the follower is drawn laterally by the cable during the forward movement of the tail-gate. The preloading or initial compression of the springs 58 which is necessary to ensure that the tail-gate 40 when released returns to the rear of the bucket and, it may be, laterally to stabilise it in its movement, is effected by a screw adjuster 61 of which one is provided at the closed end of each casing 56 and 51 and which through a slide block 68 applies initial compression to its spring 58 and enables the cable to be made fast to the carriage arm 64 while the spring is so compressed.

As an alternative to the setting screws for preloading the springs, the springhousings or casings may be furnished with telescopic ends screwthreaded or otherwise mounted on the casings so as to be capable of adjustment to apply initial compression to the springs. I Although the specific embodiment described employs compression springs for the automatic return of the tail-gate, it will be understood that the invention is not limited in this respect since other appropriate recoil mechanism could be utilised for the purpose such as fluid pressure cylinders similarly disposed to leave the top of the bucket open and free from obstruction.

Finally, it will be appreciated that if desired the wheeled bucket may be arranged as a semitrailer articulated to a self-propelled forecarriage.

What I claim is:

1. A bucket wheel scraper including a wheeled bucket, a scraper blade at the lower front edge of the bucket for passing dirt thereinto under a movable front apron, a longitudinally movable tailgate ejector for spilling earth from the bucket over the blade when required; a carriage adjacent each lateral edge of said tailgate for the support thereof, a rigid arm upstanding from each carriage and a compressed resilient element extending across the rear of said bucket and being flexibly connected to each rigid arm for automatically returning said tailgate to its position at the rear of said bucket after ejection; said flexible connections being so related to said rigid arms as to partially compensate for the moment produced by the resistance encountered, particularly by the lower part of the tailgate during ejection of the contents of the bucket.

2. A bucket wheel scraper according to claim 1 wherein the compressed resilient element is a coil compression spring housed in a casing extending laterally across the scraper in rear of the bucket and the flexible connection is a cable extending through the coil spring and having one end thereof fixed to the end of the coil spring and the other end thereof fixed to the respective rigid arm.

3. A bucket wheel scraper according to claim 1 wherein the resilient elements comprise a pair of compression springs disposed transversely of the scraper at the rear of the'bucket over the rear Wheels and housed in casings and wherein the spring axes are inclined oppositely and staggered one behind the other for the purpose specified.

ARTHUR BURNARD MCFARLANE. 

